A Hempstead man whose 7-month-old son died after being left inside a parked car is charged with negligent homicide, Nassau County police said. Videojournalist: Jim Staubitser (Aug. 21, 2013) (Credit: )

A 7-month-old Hempstead boy died after being left alone in the backseat of a car on a hot afternoon, and the father who says he forgot about the baby has been arrested.

Devon Fenner, 25, was arraigned Wednesday on a charge of criminally negligent homicide.

Nassau police said Fenner told them he accidentally left his son, Dominick, in the car parked outside his Milburn Avenue home for...

Nassau police said Fenner told them he accidentally left his son, Dominick, in the car parked outside his Milburn Avenue home for about 30 minutes Tuesday afternoon. The driver's side window, police said, had been rolled down slightly.

"Unfortunately, cracking the window on a 90-degree day doesn't do much," said Insp. Kenneth Lack, a Nassau police spokesman.

The temperature in the car at the time was 119 degrees, according to the criminal complaint.

Fenner pleaded not guilty in First District Court in Hempstead and Judge Eric Bjorneby set bail at $50,000 bond, or $25,000 cash. Fenner faces up to 4 years in prison if convicted and is due back in court next Wednesday.

About a half-hour later, he realized his son was still in the car. He went to get him and found the child had stopped breathing, police said. Fenner said he called 911. Hempstead Village police and medics found the baby "unconscious and unresponsive" and started CPR, police said.

Dominick was declared dead about 2:30 p.m. at Mercy Medical Center in Rockville Centre, and the father was arrested about two hours later.

Officers found a small amount of marijuana on Fenner, and that will be presented to a grand jury along with other evidence in the case, Lack said.

Lack said the baby likely died of heat exposure, but an autopsy will determine the cause of death.

In warning people not to leave children and pets in cars on hot days, the weather service recently tested a vehicle's internal temperature on a typical summer afternoon. The heat inside the car soared from 89 degrees to 107 in just 20 minutes, according to Upton meteorologist Joey Picca.

Stunned neighbors said they were unsure how many people lived in the house, which isn't owned by the Fenner family. "It's unbelievable," said Jocelyne Antione, 58, who lives across the street. "I can't understand how this could have happened."